The IPTV video is a high bandwidth consumption service, and packet loss is not allowed, while a network bandwidth, particularly a user link bandwidth is generally very limited. To guarantee effective launch of a video service and guarantee quality of service (QoS), a resource manager (RM) and a connection admission control (CAC) function are required to deploy in a network.
Both multicast/broadcast video (such as BTV) service and unicast video (such as VOD) service are included in an IPTV service. Because a mode of a multicast service and a mode of a unicast service differ greatly, CAC function implementations of the two modes are also different.
The multicast CAC is generally completed locally at an access node (AN). The AN judges whether the user link bandwidth satisfies a bandwidth requirement for requesting to join in a channel, or judges whether a count of channels that a user joins in is beyond a limited maximal quantity. If the CAC is failed (bandwidth insufficient or beyond the maximal quantity), a channel join request of the user is denied.
The unicast CAC function is generally completed by an independent RM. The RM appreciates the network topology, and manages an end-to-end bandwidth from a unicast video server to the user. Therefore, when the user requests a unicast video service, a service server can request resources from the RM. The RM judges the satisfaction of the end-to-end bandwidth, and returns a result of requesting resources. The service server decides whether to admit a service according to the result of requesting resources.
In an existing solution, resources are reserved for the multicast service and the unicast service each on a user link, and are not occupied by each other. The AN implements a local multicast CAC function, and the RM completes an end-to-end CAC function from the unicast video server to the user. The unicast CAC function and the multicast CAC function of the solution are independent of each other, and keep consistent with the existing network. However, the multicast service and the unicast service are not able to share bandwidth resources and thus resulting in waste of the bandwidth resources. Moreover, the solution has a limited application scenario, that is, the solution is only suitable for a scenario of a sufficient user link bandwidth.
In another existing solution, when the user joins in a certain channel, the AN proactively reports information of the channel that the user joins in, directly sends the information to the RM or sends the information to the RM through a broadband network gateway (BNG), and the RM judges whether the user link bandwidth satisfies the requirement. If the requirement is not satisfied, the AN is notified to reject a user join request.
Such processes for the AN to report multicast user join information, and for the RM to perform the CAC in a unified way unifies the implementation of the multicast and implementation of the unicast. However, realization of the solution is complex, and the switching frequency of the multicast service is higher than the switching frequency of the unicast service. The case that a large number of TV users frequently switching channels will result in a great deal of information interaction, which imposes a very high requirement on the performance of the AN. Furthermore, the channel switching of the multicast service is required to interact with the RM, the switching time is long, and thus the user experience is poor.